This invention relates to disk drive devices, and more particularly, to structures that seal an opening through which a flexible printed circuit board (FPC) passes from the inside of a disk drive housing to the outside of the disk drive housing.
In recent years, low cost, high performance disk drives have been in demand as the use of personal computers has spread. To achieve low cost and high performance, new structures are required.
In general, a magnetic or other disk drive device has a housing that includes a base and a cover, one on top of the other. Within the housing are mechanisms such as a spindle motor that rotates a magnetic disk, and an actuator that supports heads that read data from or write data to the magnetic disk. A control printed circuit board, on which is located a controller that controls these mechanisms, is located on the outside of the housing. The sending and receiving of signals between the mechanisms within the housing and the control printed circuit board take place through an FPC.
In order to extend the FPC from the inside of the disk drive housing to the outside of the housing, the housing must have an opening in it. However, if this opening is not adequately sealed, problems will arise, such as an increase in signal noise and the entry of foreign matter to the inside of the housing, ruining the reliability of the disk drive device. As a consequence, there is a need for structures which create an airtight seal in the housing when extending the FPC to the outside of the housing.
FIG. 1 shows one known approach for extending the FPC to the outside of the disk drive housing. In FIG. 1, a magnetic disk drive device has a base 2. The disk drive housing is formed by placing a cover (not shown) on top of the base of the housing. On an inside bottom surface 3 of the housing base 2 are installed components such as magnetic disks 5 that store data, magnetic heads 6 that read and write data to the magnetic disks 5, and an actuator 7 that supports the magnetic heads 6 and drives the heads 6 in the radial direction of the magnetic disks 5. A controller, which controls mechanisms such as the actuator 7 and magnetic heads 6, is located on a printed circuit board, installed on the outside bottom surface of the disk drive housing 1. The sending and receiving of signals between the mechanisms on the inside of the housing and the control printed circuit board 9 on the outside of the housing takes place through the FPC 8.
As shown in FIG. 1, the FPC 8 extends from a housing base alignment surface for installing the housing cover to the base 2, and is then placed in the position designated for the control printed circuit board 9. In addition, double-sided adhesive tape is applied to an alignment surface 31 to set the FPC 8 firmly in place on the base 2. In this condition, the housing is then sealed tightly by placing the cover on top of the base 2.
FIG. 2 shows another prior art system, in which the FPC 8 has been relocated to the outside of the housing. In FIG. 2, a connector with a plastic frame is attached to an end section of the FPC 8 and the control printed circuit board 9 (not shown). Further, a hole (not shown) is created in the housing base 2, and the connector 41 is held over the hole by screws 42. The periphery of the hole is filled with a packing material (not shown) such as rubber, and a tight seal of the housing 2 is established by inserting the packing material between the connector 41 and the inside bottom surface 3 of the housing base 2. The pins (not shown) of the connector 41 are exposed at the bottom of the base 2 to allow an electrical connection with the control printed circuit board 9.
In the first prior art system, a tight seal of the housing is accomplished by placing a strip of double-sided surface adhesive tape 32 between the FPC 8 and the base alignment surface 31. Since the structure of the first prior art device is simple, placing the FPC 8 on the outside of the housing 1 can be accomplished at relatively low cost. However, because the FPC 8 is extended through the base alignment surface 31, and because its installation position is across a bottom surface of the housing 1, the length of the wiring increases. A long length of wire allows noise to get into the signals, creating the problem of obstructed high speed signal transfer.
On the other hand, in the prior art of FIG. 2, the FPC 8 extends through the hole created in the inside bottom surface 3 of the housing base 2. As a consequence, the wiring length can be relatively short, which makes it difficult for noise to get into the signals, which is a benefit to high speed signal transfer. However, because large areas are necessary to create openings for the connector 41 and the screws 42, there are limitations on wire layout freedom, which makes it difficult for the ideal wiring route to be taken. Moreover, because components such as the connector 41, hole packing material (not shown), and screws 42 are required, and because screw holes have to be formed and a production step added to fix the connector 41 in place with screws, there are problems of higher cost of parts and higher cost of production. Thus, there is a need for disk drive devices that allow the transfer of high quality signals at low cost.
Accordingly, one object of this invention is to provide new and improved reliable disk drive devices.
An additional object is to provide new and improved compact disk drive devices having low production cost.
Yet another object is to provide new and improved disk drive devices that allow high quality signal transfer to take place.
The above-listed objects are met or exceeded by the present invention, in which a magnetic or other disk drive device has one or more heads for writing or reading data on disk media, and an actuator for driving the heads in the radial direction on the disk media. The head and actuator are located on an inside surface of a base, and are controlled by components located outside the base by way of signal lines which pass through an opening in the base. The opening is sealed with a cover.
In one embodiment, the signal lines are part of a flexible printed circuit (FPC) or the like which has an expanded area which surrounds the opening. The signal lines extend through a space within the expanded area and the opening to the outside of the base. The cover is placed over the opening and is adhesively secured to the PFC around the periphery of the opening to seal the opening.
With this invention, it is possible to obtain signals that travel fairly directly from the bottom surface of the base to the heads, which shortens the length of the wiring. This reduces the electrical noise that gets into the signals, and allows faster signal speed. Further, because a connector is not required and because a production step to attach the connector is not required, the production cost can be reduced. This is due to a reduction in the number of parts as well as a reduction in the number of production steps.
In particular, by installing the FPC to the base using adhesion, screws are not required to hold the FPC in place. Because of this, no space is required for screw holes, which allows fewer restrictions in terms of component layout. In addition to this, a production step to place screw holes in the base is not required, reducing production cost.
Further, by making the cover component conductive, the intrusion of noise from the housing will be restricted. This further prevents the malfunctioning of the mechanisms located within the disk drive housing.
In addition to this, by creating an expanded area on the FPC that surrounds the end section of the FPC, and by having this expanded area adhere tightly to the periphery of the opening, the surface that adheres tightly to the cover component on the FPC can be flat, eliminating gaps between the FPC and the cover component. As a result, the benefit is a positive airtight seal of the housing.